How far can an up flush toilet be located from the main drain. There will also be a shower and sink that will be hooked up to the main holding tank. My ideal location is about 25-30 feet away from the main drain. It will be hooked up to this drain that travels the length of the house (30-40 feet) and then turns 90 degrees where it travels about 10 feet before it exits the house into the septic tank. Any ideas. The alternative location is much closer to the main drain and septic but it is definitely not the best location in the basement... Any ideas are appreciated!